## Fundamental Units involved in Energy Measurements

Power = Energy/TimeFundamental Units of Energy

Approximate Cost: $0.15 per kwh (May change significantly based on location and season of use).

**Joule (J)**: The Joule is the SI unit of energy, defined as the amount of work done when a force of one newton is applied over a distance of one meter. It's also the energy dissipated as heat when an electric current of one ampere passes through a resistance of one ohm for one second.**Calorie (cal)**: Another unit of energy commonly used in chemistry and biology, especially in nutritional contexts. One calorie is defined as the amount of heat needed to raise the temperature of one gram of water by one degree Celsius. There are 4.184 joules in one calorie.**Watt-hour (Wh)**: A unit of energy commonly used to measure electrical energy, especially for electric utilities and appliances. One watt-hour represents the amount of energy consumed by a device that uses one watt of power for one hour. There are 3,600 joules in one watt-hour.**British Thermal Unit (BTU)**: A unit of heat energy used primarily in the United States, defined as the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit. One BTU is approximately 1,055 joules.

**Work**: The work done by a force is the product of the force applied and the distance moved by the force in the direction of the force. The formula is: W=F×dW=F×d where WW is work in joules, FF is force in newtons, and dd is distance in meters.**Kinetic Energy**: The energy of an object in motion is called kinetic energy, calculated by the formula: KE=12mv2KE=21mv2 where KEKE is kinetic energy in joules, mm is mass in kilograms, and vv is velocity in meters per second.**Potential Energy**: The energy stored in an object due to its position in a force field (commonly gravitational) is known as potential energy. The formula for gravitational potential energy near the Earth's surface is: PE=mghPE=mgh where PEPE is potential energy in joules, mm is mass in kilograms, gg is the acceleration due to gravity (9.81m/s29.81m/s2 on the surface of the Earth), and hh is the height in meters.**Heat Energy**: The energy transferred from one system to another due to a temperature difference is quantified by the formula: Q=mcΔTQ=mcΔT where QQ is the heat energy in joules, mm is the mass of the substance in kilograms, cc is the specific heat capacity of the substance (J/kg⋅KJ/kg⋅K), and ΔTΔT is the change in temperature in Kelvin.**Electrical Energy**: The energy used by an electrical appliance can be calculated as: E=P×tE=P×t where EE is energy in watt-hours, PP is power in watts, and tt is time in hours.

Approximate Cost: $0.15 per kwh (May change significantly based on location and season of use).

Appliance |
watt |
Hours/Day | kwh |

40-49 in Plasma |
400 | 4 | 1.6 |

Dishwasher | 1200 | 1 | 1.2 |

Refrigerator | 500 | 10 | 5.0 |

Dryer | 5000 | 0.5 | 2.5 |

Washer | 500 | 0.5 | 0.25 |

Water Heater |
4500 | 2.5 | 11.25 |

Computer | 300 | 8 | 2.4 |

Portable Heater |
1500 | 4 | 6.0 |